The overall objective is to identify and analyze the genetic components of a developmental system. The experimental system is the sexual reproductive apparatus of Neurospora. The approach is to compare normal development with the development of an array of mutants showing various alterations of the system, for example number of spores per ascus, shape of spores, or structure of the perithecium. The primary observations will be made with electron microscopy, with attention being focused particularly on membranes, spindle-pole bodies, and vacuoles, which are organelles known from our previous work to be key participants in spore excision. The effects of altered spatial relationships among these organelles will be studied in double mutants where one of the mutations alters ascus shape. Indirect immunofluorescence will be utilized for visualizing the relationship of actin and tubulin networks to spindle-pole bodies, membranes, and nuclei. Where aberrant function of membranes in the mutants has already been established, the chemical composition of the membranes will be compared with that of wild type.